Sub surface safety valves are provided in oil and gas wells to shut off the flow of product from the formation towards the surface in situations where continuing flow of product could be dangerous. It is now universal practice that all producing wells should include a functioning sub surface safety valve. This means that if a sub surface safety valve fails and it is uneconomic to work over the well installation and provide a new valve, the whole well will have to be shut down.
Typically sub surface safety valves are operated via hydraulic control lines from the surface of the well. They are generally arranged to be fail safe such that if the supply of hydraulic fluid is interrupted to the valve, the valve will close. It is of course possible for sub surface safety valves to fail in use or for there to be some damage to the control line.
At least some sub surface safety valves are installed as tubing retreivable safety valves such that if the valve itself fails it may be withdrawn from the well without decommissioning the whole well and replaced by a new valve. In such circumstances the new valve will automatically connect into the control line ports to allow control of the new valve. Even with such a system in place, if there is some problem with the control line, a situation can be reached where it is not possible to conventionally provide a functioning sub surface safety valve and the whole well may need to be shut down at least for work over.
The present invention is directed at providing alternative solutions.